Allergy medications are available as pills, liquids, inhalers, nasal sprays, eyedrops, skin creams and shots (injections). Some are available over-the-counter; others are available by prescription only. Here's a summary of the types of allergy medications and why they're used.

Antihistamines block histamine, a symptom-causing chemical released by your immune system during an allergic reaction.

Pills and liquids

Oral antihistamines, available over-the-counter and by prescription, ease a runny nose, itchy or watery eyes, hives, swelling, and other signs or symptoms of allergies. Because some of these drugs can cause drowsiness and fatigue, take them with caution when you need to drive or do other activities that require alertness.

Eyedrops

Antihistamine eyedrops, available over-the-counter or by prescription, can ease itchy, red, swollen eyes. These drops might have a combination of antihistamines and other medicines.

Side effects might include headache and dry eyes. If antihistamine drops sting or burn, try keeping them in the refrigerator or using refrigerated artificial-tear drops before you use the medicated drops. Examples include:

Azelastine (Optivar)

Emedastine (Emadine)

Ketotifen (Alaway)

Olopatadine (Pataday, Patanol, Pazeo)

Pheniramine (Visine-A, Opcon-A, others)

Decongestants are used for quick, temporary relief of nasal and sinus congestion. They can cause insomnia, headache, increased blood pressure and irritability. They're not recommended for pregnant women or for people with high blood pressure, cardiovascular disease, glaucoma or hyperthyroidism.

Pills and liquids

A number of oral allergy medications contain a decongestant and an antihistamine. Examples include:

Cetirizine and pseudoephedrine (Zyrtec-D)

Desloratadine and pseudoephedrine (Clarinex-D)

Fexofenadine and pseudoephedrine (Allegra-D)

Loratadine and pseudoephedrine (Claritin-D)

Nasal sprays and drops

Nasal decongestant sprays and drops relieve nasal and sinus congestion if used only for a short time. Repeated use of these drugs for more than three consecutive days can result in a cycle of recurring or worsening congestion. Examples include:

Nasal sprays

Corticosteroid sprays prevent and relieve stuffiness, sneezing and runny nose. Side effects can include an unpleasant smell or taste, nasal irritation, and nosebleeds. Examples include:

Budesonide (Rhinocort)

Fluticasone furoate (Flonase Sensimist, Veramyst)

Fluticasone propionate (Flonase Allergy Relief)

Mometasone (Nasonex)

Triamcinolone (Nasacort Allergy 24 Hour)

For people who are bothered by the feeling of liquid running down their throats or the taste of the above, there are two aerosol formulas:

Beclomethasone (Qnasl)

Ciclesonide (Zetonna)

Inhalers

Inhaled corticosteroids are often used daily as part of treatment for asthma caused or complicated by reactions to airborne allergy triggers (allergens). Side effects are generally minor and can include mouth and throat irritation and oral yeast infections.

Eyedrops

Corticosteroid eyedrops are used to relieve persistent itchy, red or watery eyes when other interventions aren't effective. A physician specializing in eye disorders (ophthalmologist) usually monitors the use of these drops because of the risk of vision impairment, cataracts, glaucoma and infection. Examples include:

Fluorometholone (Flarex, FML)

Loteprednol (Alrex, Lotemax)

Prednisolone (Omnipred, Pred Forte, others)

Pills and liquids

Oral corticosteroids are used to treat severe symptoms caused by all types of allergic reactions. Long-term use can cause cataracts, osteoporosis, muscle weakness, stomach ulcers, increased blood sugar (glucose) and delayed growth in children. Oral corticosteroids can also worsen hypertension.

Prescription oral corticosteroids include:

Prednisolone (Prelone)

Prednisone (Prednisone Intensol, Rayos)

Methylprednisolone (Medrol)

Skin creams

Corticosteroid creams relieve allergic skin reactions such as itching, redness, scaling or other irritations. Some low-potency corticosteroid creams are available without a prescription, but talk to your doctor before using these drugs for more than a few weeks.

Side effects can include skin discoloration and irritation. Long-term use, especially of stronger prescription corticosteroids, can cause thinning of the skin and disruption of normal hormone levels. Examples include:

Betamethasone (Dermabet, Diprolene, others)

Desonide (Desonate, DesOwen)

Hydrocortisone (Cortaid, Micort-HC, others)

Mometasone (Elocon)

Mast cell stabilizers block the release of immune system chemicals that contribute to allergic reactions. These drugs are generally safe but usually need to be used for several days to reach full effect. They're usually used when antihistamines are not working or not well-tolerated.

Nasal spray

Generic over-the-counter nasal sprays are sold as cromolyn.

Eyedrops

Prescription eyedrops include the following:

Cromolyn (Crolom)

Lodoxamide (Alomide)

Pemirolast (Alamast)

Nedocromil (Alocril)

A leukotriene inhibitor is a prescription medication that blocks symptom-causing chemicals called leukotrienes. This oral medication relieves allergy signs and symptoms including nasal congestion, runny nose and sneezing. Only one type of this drug, montelukast (Singulair), is approved for treating hay fever.

In some people, leukotriene inhibitors can cause psychological symptoms such as irritability, anxiousness, insomnia, hallucinations, aggression, depression, and suicidal thinking or behavior.

Immunotherapy is carefully timed and gradually increased exposure to allergens, particularly those that are difficult to avoid, such as pollens, dust mites and molds. The goal is to train the body's immune system not to react to these allergens.

Immunotherapy might be used when other treatments aren't effective or tolerated. It might help prevent the development of asthma in some people.

Shots

Immunotherapy may be administered as a series of injections, usually one or two times a week for three to six months. This is followed by a series of less frequent maintenance shots that usually continue for three to five years.

Side effects might include irritation at the injection site and allergy symptoms such as sneezing, congestion or hives. Rarely, allergy shots can cause anaphylaxis, a sudden life-threatening reaction that causes swelling in the throat, difficulty breathing, and other signs and symptoms.

Sublingual immunotherapy (SLIT)

With this type of immunotherapy, you place an allergen-based tablet under your tongue (sublingual) and allow it to be absorbed. This daily treatment has been shown to reduce runny nose, congestion, eye irritation and other symptoms associated with hay fever. It also improves asthma symptoms and may prevent the development of asthma.

SLIT tablets contain extracts from pollens of different types of grass, including the following:

Epinephrine shots are used to treat anaphylaxis, a sudden, life-threatening reaction. The drug is administered with a self-injecting syringe and needle device (autoinjector). You might need to carry two autoinjectors and wear an alert bracelet if you're likely to have a severe allergic reaction to a certain food, such as peanuts, or if you're allergic to bee or wasp venom.

A second injection is often needed. Therefore, it's important to call 911 or get immediate emergency medical care.

Your health care provider will train you on how to use an epinephrine autoinjector. It is important to get the type that your doctor prescribed, as the method for injection may differ slightly for each brand. Also, be sure to replace your emergency epinephrine before the expiration date.

Examples of these medications include:

Adrenaclick

Auvi-Q

EpiPen

EpiPen Jr.

Work with your doctor to choose the most effective allergy medications and avoid problems. Even over-the-counter allergy medications have side effects, and some allergy medications can cause problems when combined with other medications.

It's especially important to talk to your doctor about taking allergy medications in the following circumstances:

You're pregnant or breast-feeding.

You have a chronic health condition, such as diabetes, glaucoma, osteoporosis or high blood pressure.

You're taking other medications, including herbal supplements.

You're treating allergies in a child. Children need different doses of medication or different medications from adults.

You're treating allergies in an older adult. Some allergy medications can cause confusion, urinary tract symptoms or other side effects in older adults.

You're already taking an allergy medication that isn't working. Bring the medication with you in its original bottle or package when you see your doctor.

Keep track of your symptoms, when you use your medications and how much you use. This will help your doctor figure out what works best. You might need to try a few medications to determine which are most effective and have the least bothersome side effects for you.

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